Posted by rocksea on 04 Sep 2016
It is nesting season for the baya weavers!
Baya weaver birds are small, sparrow-size birds which resemble the sparrows during the non-breeding season. During May-June, as the breeding season approaches, their gonads (sexual glands) become active and the adult males develop yellow and black color plumage on head, breast and throat; and their bills also darken. By the time the monsoon starts, the males are in bright yellow summer colors, and ready for breeding through the monsoon season (June-September).
Why do they breed during the summer monsoon? Obviously, the grass is green during this side of the monsoon! Baya weavers forage in flocks for seeds on wild grass like these below, which are plenty after the monsoon rains. This is also the time when insects are plenty, especially to feed their young. How many bayas can you count in the image below?!
Nesting success? Baya weaver nests are exclusively built by the males and then displayed to the females. What are the factors on which the female makes it selection? Among birds, elaborate nests and decorations built by males may help females to assess a male’s quality. One of the most popular architectural attributes of the weaver nest is the entrance tube, which can get as long as 90 cm. Female birds are also selective in choosing nests which provides safety (in terms of nest height and location). So what does the baya weaver base their selection on? Is it the architecture or the location?
Safer on thorny trees: Observation shows that the female weavers are inclined towards nests which are safely located in thorny trees, farther away from the trunk and situated high above the ground. Thornless trees have higher rates of snake predation than thorny trees. Nesting success also increases with with thickness of the supporting branch and for nests which are woven with fine fiber. Thick branches may stabilize nests during strong monsoon winds, and may also be less likely to break.
Despite these precautions, garden lizards like the one above, and tree mouse do occasionally raid these nests.
Some history: Baya weavers and their unique nesting nature were first recorded in Ain-i-Akbari, the 16th-century document recording the administration of Akbar’s empire, and which is part of the a much larger document, the Akbarnama. The Volume III translation by Colonel H. S. Jarret talks about wild/domesticated bayas: “The baya is like a wild sparrow but yellow. It is extremely intelligent, obedient and docile. It will take small coins from the hand and bring them to its master, and will come to a call from a long distance. Its nests are so ingeniously constructed as to defy the rivalry of clever artificers.”
Species: Ploceus philippinus
English: Baya weaver
Location: IITM colony, Pune, Maharashtra
Date: 3 Sep 2016
1. Balasubramanian, K. S., & Saxena, R. N. (1973). Effect of pinealectomy and photoperiodism in the reproduction of Indian weaver birds, Ploceus philippinus. Journal of Experimental Zoology, 185(3), 333-340.
2. Fazl, A., & Jarrett, H. S. (1983). The Ain-i-Akbari:. Royal Asiatic Society of Bengal. (No. 61).
3. Quader, S. (2006). What makes a good nest? Benefits of nest choice to female Baya Weavers (Ploceus philippinus). The Auk, 123(2), 475-486.